GoingDown (this US Navy button's finder) wrote:
> I wonder what the significance of the different stamp (maker?) on the back is
?
Your button's backmark saying Superior Quality is a generic quality "rating" used by several manufacturers for their metal buttons -- a rating-system which has been in existence for about 200 years. The only important significance the Superior Quality marking on your button has is that the lettering is non-serifed (plain block) lettering -- which is seldom found on pre-20th-Century button backmarks.
Also importaant for time-dating your button is the fact that the eagle's head is turned toward the eagle's left side (the viewer's right). The emblem was changed to having the eagle looking toward its right side (the viewer's left) in 1943, and that design continues to the present day.
So, in summary, your button most probably dates from the start of the 20th-Century through 1942.
For anybody here who doesn't already know:
Examine the diagram below (made by BigCypressHunter, I think) for clarification about serifed and non-serified lettering. The red lines represent the serifs -- which are absent on "plain block" lettering.